6,314 research outputs found

    A H2 PEM fuel cell and high energy dense battery hybrid energy source for an urban electric vehicle

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    Electric vehicles are set to play a prominent role in addressing the energy and environmental impact of an increasing road transport population by offering a more energy efficient and less polluting drive-train alternative to conventional internal combustion engine (ICE) vehicles. Given the energy (and hence range) and performance limitations of electro-chemical battery storage systems, hybrid systems combining energy and power dense storage technologies have been proposed for vehicle applications. The paper discusses the application of a hydrogen fuel cell as a range extender for an urban electric vehicle for which the primary energy source is provided by a high energy dense battery. A review of fuel cell systems and automotive drive-train application issues are discussed, together with an overview of the battery technology. The prototype fuel cell and battery component simulation models are presented and their performance as a combined energy/power source assessed for typical urban and sub-urban driving scenario

    Assessing the marginal dollar value losses to an estuarine ecosystem from an aggressive alien invasive crab

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    This paper reports on a case study to establish dollar values for loss of biodiversity in the New Zealand coastal marine environment. The study uses the European Shore Crab (Carcinas maenas) as the example alien invasive species and the Pauatahanui Inlet, Wellington, New Zealand, as the ecosystem representative of the coastal marine environment. Choice modelling is the stated preference tool used to elicit marginal dollar values for these various attributes of the inlet. Reallocation of existing government expenditure is used as the payment mechanism. Results indicate a wide range of dollar values for the marginal losses to the environment, with no clear trend on a distance-decay relationship. The probability distributions of the dollar values of the environmental attributes tended to have a concentration around the median with very wide tails, especially on the high side. This indicates that most people generally agreed on a dollar value, but a very few individuals expressed extremely high values. The study concludes that the dollar values for loss of biodiversity and other environmental attributes do provide useful information to decision makers, but considerable caution needs to be exercised when applying these values in benefit cost studies. Marginal rate of substitution estimates between environmental attributes will be useful for estimating money values for attributes identified given future work estimates a statistically significant money value for one

    Electrocardiographic markers of structural heart disease and predictors of death in 2332 unselected patients undergoing outpatient Holter recording

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    To test the hypothesis that the QS interval of ventricular ectopic beats (VEBs) (ventricular ectopic QS interval, VEQSI) would provide a marker for the presence of structural heart disease and a predictor of mortality

    Greater engagement with health information is associated with adoption and maintenance of healthy lifestyle behaviours in people with MS

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    Health communication offers an important means for patients to make informed decisions for illness self-management. We assessed how the level of engagement with selected health information at baseline is associated with the adoption and maintenance of lifestyle behaviours at a 5-year follow-up in people with multiple sclerosis (MS). Non-engagers were compared to engagers of information delivered online and print (medium), and with engagers who additionally attended a live-in workshop (high). Engagement was assessed against lifestyle behaviours by log-binomial regression. Information engagers had higher education, and were less likely to have severe disability, clinically significant fatigue, or obesity. Medium and high baseline engagement was associated with adopting healthy behaviours for omega 3 supplementation (RR = 1.70; 95%CI: 1.02-2.84), physical activity (RR = 2.16; 95%CI: 1.03-4.55), and dairy non-consumption (RR = 3.98; 95%CI: 1.85-8.56) at 5 years; associations were stronger among high engagers. Only high baseline engagement was associated with maintaining behaviours from baseline to 5 years, specifically for omega-3 (RR = 1.26; 95%CI: 1.06-1.49) and vitamin D supplementation (RR = 1.26; 95%CI: 1.04-1.54) and dairy non-consumption (RR = 1.47; 95%CI: 1.03-2.10). Health communication that includes face-to-face information delivery and practical tools for implementation in daily living may be optimal for adopting and maintaining lifestyle behaviours in people with MS

    Correlation of metallothionein expression with apoptosis in nasopharyngeal carcinoma

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    The expression of metallothionein (MT), an intracellular ubiquitous low molecular weight protein thiol with antioxidant properties, was studied in nasopharyngeal cancer (NPC) and correlated with the apoptotic index. Immunohistochemical staining of randomly selected, formalin-fixed and paraffin-embedded normal and malignant nasopharyngeal tissues were analysed for the expression of MT using the commercially available E9 antibody directed against MT I and MT II isoforms. The corresponding apoptosis labelling indices were evaluated by the TUNEL method. Localization of MT at the ultrastructural level was studied by immunogold labelling. All the tumour sections (17 specimens) showed MT-immunopositivity. A direct correlation between the percentage of MT-positive cells and the staining intensity was noted (P< 0.001; Pearson's r = 0.95). There was absence of cytoplasmic staining and only nuclear staining (with localization in the nucleoplasm) was demonstrated in the tumour cells. In normal epithelium of the nasopharynx, the basal layer was stained. An inverse relationship was observed between the level of MT expression and the apoptotic index in the NPC tissues (P = 0.0059; Pearson's r = –0.6380). The results suggest that overexpression of MT in NPC may protect the tumour cells from entering into the apoptotic process and thereby contribute to tumour expansion. Preferential localization of MT in the nuclei of NPC cells may possibly enhance radioresistance since radiotherapy is known to eradicate tumour cells by free radical-induced apoptosis. © 2000 Cancer Research Campaig

    Effect of Inflow and Infiltration in Sewerage System of Residential Area, Kuantan, Pahang

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    Inflow and infiltration is a phenomenon in sewerage systems that can have negative effects on the environment and human health if not treated properly. Collaboration has been made between Universiti Malaysia Pahang (UMP) and Indah Water Konsortium Sdn. Bhd. (IWK) where the purpose is to evaluate the amount of inflow and infiltration happening in sewerage systems of residential areas in Kuantan. For this part of the study, one sewer pipeline (MH92a–MH92b) was selected at the residential area of Bandar Putra, having a population equivalent of 1694. The method used in this research was the Flowrate method to tabulate data. ISCO 2150 and 4250 Area Velocity Flowmeters were used to measure flow rate data in the sewer pipeline, whereas ISCO 674 Rain Gauge was used to collect rainfall intensity data. Calibration of all the equipment was done at the Hydrology and Hydraulic Laboratory in UMP. The data was collected for 41 days with each measurement separated by an interval of five minutes. The result shows that the average percentage Infiltration Rate of Qpeak and Qave in this residential catchment were 10.3% and 26.5% which is higher than the value mentioned in Hammer and Hammer (2012). Inflow and infiltration is a real concern, so more study is required to determine whether revision of the infiltration rate recommended in the Malaysian Standard is needed

    A narrative review of cracks in teeth: Aetiology, microstructure and diagnostic challenges

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    Objectives To summarize the available evidence of crack formation in teeth and to discuss the limitations of the current clinical diagnostic modalities for crack detection in teeth. Background Cracks are a common clinical finding in teeth and yet clinicians still struggle to identify the full extent and orientation of cracks for their appropriate timely management. The biomechanics of crack development can be due to multiple factors and can differ from an unrestored tooth to a restored or endodontically treated tooth. Data & sources This narrative review has been designed following the guidelines published by Green et al. 2006 [1] Published literature in the English language that addresses the objectives of this review up to July 2022 was sourced from online databases and reference lists. The relevance of the papers was assessed and discussed by two reviewers. A total of 101 publications were included in this narrative review. Conclusions The initiation and development of cracks in teeth are likely linked to an interplay between the masticatory forces and fracture resistance of the remaining tooth structure. From the identified literature, the quality and quantity of remaining tooth structure in a restored or endodontically-treated tooth affects the biomechanics of crack development compared to an unrestored tooth. The extent, orientation, and size of the cracks do affect a clinician's ability to detect cracks in teeth. There is still a need to develop reliable diagnostic tools that will accurately identify cracks in teeth beneath restorations to enable effective monitoring of their propagation and provide appropriate interventions. Clinical significance The development and propagation of cracks in an unrestored tooth differ greatly from a restored and endodontically treated tooth; mainly linked to the quantity and quality of the remaining tooth structure and the forces acting on them. Identifying the extent of cracks in teeth remains challenging for early clinical intervention

    Par3 integrates Tiam1 and phosphatidylinositol 3-kinase signaling to change apical membrane identity

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    Pathogens can alter epithelial polarity by recruiting polarity proteins to the apical membrane, but how a change in protein localization is linked to polarity disruption is not clear. In this study, we used chemically induced dimerization to rapidly relocalize proteins from the cytosol to the apical surface. We demonstrate that forced apical localization of Par3, which is normally restricted to tight junctions, is sufficient to alter apical membrane identity through its interactions with phosphatidylinositol 3-kinase (PI3K) and the Rac1 guanine nucleotide exchange factor Tiam1. We further show that PI3K activity is required upstream of Rac1, and that simultaneously targeting PI3K and Tiam1 to the apical membrane has a synergistic effect on membrane remodeling. Thus, Par3 coordinates the action of PI3K and Tiam1 to define membrane identity, revealing a signaling mechanism that can be exploited by human mucosal pathogens

    Design and Shape Optimization of Strain Gauge Load Cell for Axial Force Measurement for Test Benches

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    The load cell is an indispensable component of many engineering machinery and industrial automation for measuring and sensing force and torque. This paper describes the design and analysis of the strain gauge load cell, from the conceptional design stage to shape optimization (based on the finite element method (FEM) technique) and calibration, providing ample load capacity with low-cost material (aluminum 6061) and highly accurate force measurement. The amplifier circuit of the half Wheatstone bridge configuration with two strain gauges was implemented experimentally with an actual load cell prototype. The calibration test was conducted to evaluate the load cell characteristics and derive the governing equation for sensing the unknown load depending on the measured output voltage. The measured sensitivity of the load cell is approximately 15 mV/N and 446.8 µV/V at a maximum applied load of 30 kg. The findings are supported by FEM results and experiments with an acceptable percentage of errors, which revealed an overall error of 6% in the worst situation. Therefore, the proposed load cell meets the design considerations for axial force measurement for the laboratory test bench, which has a light weight of 20 g and a maximum axial force capacity of 300 N with good sensor characteristic

    Total coloring of 1-toroidal graphs of maximum degree at least 11 and no adjacent triangles

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    A {\em total coloring} of a graph GG is an assignment of colors to the vertices and the edges of GG such that every pair of adjacent/incident elements receive distinct colors. The {\em total chromatic number} of a graph GG, denoted by \chiup''(G), is the minimum number of colors in a total coloring of GG. The well-known Total Coloring Conjecture (TCC) says that every graph with maximum degree Δ\Delta admits a total coloring with at most Δ+2\Delta + 2 colors. A graph is {\em 11-toroidal} if it can be drawn in torus such that every edge crosses at most one other edge. In this paper, we investigate the total coloring of 11-toroidal graphs, and prove that the TCC holds for the 11-toroidal graphs with maximum degree at least~1111 and some restrictions on the triangles. Consequently, if GG is a 11-toroidal graph with maximum degree Δ\Delta at least~1111 and without adjacent triangles, then GG admits a total coloring with at most Δ+2\Delta + 2 colors.Comment: 10 page
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